Search Publications
On-axis spectroscopy of the host galaxies of 20 optically luminous quasars at z ~ 0.3
Magain, P.; Jahnke, K.; Jablonka, P. +4 more
We present the analysis of a sample of 20 bright low-redshift quasars (MB < -23 and z < 0.35) observed spectroscopically with the Very Large Telescope (VLT). The Focal Reducer/low dispersion Spectrograph (FORS1) spectra, obtained in Multi-Object Spectroscopy (MOS) mode, allow to observe simultaneously the quasars and several refer…
High-redshift Fanaroff-Riley type II radio sources: large-scale X-ray environment
Hardcastle, M. J.; Croston, J. H.; Worrall, D. M. +1 more
We investigate the properties of the environment around 20 powerful radio galaxies and quasars at redshifts between 0.45 and 1. Using XMM-Newton and Chandra observations we probe the spatial distribution and the temperature of the cluster gas. We find that more than 60 per cent of powerful radio sources in the redshift range of our sample lie in a…
The supermassive black hole in NGC4486a detected with SINFONI at the Very Large Telescope
Pannella, M.; Saglia, R. P.; Nowak, N. +4 more
The near-infrared (IR) integral field spectrograph SINFONI at the European Southern Observatory Very Large Telescope opens a new window for the study of central supermassive black holes. With a near-IR spatial resolution similar to Hubble Space Telescope optical and the ability to penetrate dust, it provides the possibility to explore the low-mass…
The Chandra view of galaxy mergers
Ponman, Trevor J.; Brassington, Nicola J.; Read, Andrew M.
From a Chandra survey of nine interacting galaxy systems the evolution of X-ray emission during the merger process has been investigated. It is found that the X-ray luminosity peaks ~300Myr before nuclear coalescence, and then dips, even though we know that rapid and increasing activity is still taking place at this time. It is likely that this dr…
The Galaxy Evolution Explorer UV emission in shell galaxies: tracing galaxy `rejuvenation' episodes
Rich, R. M.; Buson, L. M.; Marino, A. +6 more
We present the Galaxy Evolution Explorer (GALEX) far-ultraviolet (FUV) and near-ultraviolet (NUV) imaging of three nearby shell galaxies, namely NGC 2865, NGC 5018 and NGC 7135 located in low-density environments.
The system of shells and fine structures visible in the optical is detected in the NUV image of NGC 2865 and in both NUV and FUV i…The impact of accretion disc winds on the X-ray spectrum of AGN - I. XSCORT
Schurch, N. J.; Done, C.
The accretion disc in active galactic nucleus (AGN) is expected to produce strong outflows, in particular an ultraviolet (UV)-line-driven wind. Several observed spectral features, including the soft X-ray excess, have been associated with the accretion disc wind. However, current spectral models of the X-ray spectrum of AGN observed through an acc…
Highly ionized plasma in the Large Magellanic Cloud: evidence for outflows and a possible galactic wind
Lehner, N.; Howk, J. C.
Based on an analysis of the interstellar highly ionized species CIV, SiIV, NV and OVI observed in the Far Ultraviolet Spectroscopic Explorer (FUSE) and Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) E140M spectra of four hot stars in the Large Magellanic Cloud (LMC), we find evidence for a hot LMC halo fed by energetic outf…
A quantitative link between globular clusters and the stellar haloes in elliptical galaxies
Forte, Juan C.; Faifer, Favio; Geisler, Doug
This paper explores the quantitative connection between globular clusters and the 'diffuse' stellar population of the galaxies they are associated with. Both NGC 1399 and NGC 4486 (M87) are well suited for this kind of analysis due to their large globular cluster populations.
Proper motion dispersions of red clump giants in the galactic bulge: observations and model comparisons
Gerhard, Ortwin; Sumi, Takahiro; Mao, Shude +3 more
Red clump giants (RCGs) in the Galactic bulge are approximate standard candles and hence they can be used as distance indicators. We compute the proper motion dispersions of RCG stars in the Galactic bulge using the proper motion catalogue from the second phase of the Optical Gravitational Microlensing Experiment (OGLE-II) for 45 fields. The prope…
Draco, a flawless dwarf galaxy*
Chapman, S.; Martin, N. F.; Irwin, M. J. +2 more
The Draco dwarf spheroidal galaxy (dSph), with its apparent immense mass-to-light ratio and compact size, holds many clues to the nature of the enigmatic dark matter. Here we present deep photometric studies of this dwarf galaxy, undertaken with the MegaCam Camera at the Canada-France-Hawaii Telescope, the Wide Field Camera at the Isaac Newton Tel…